Pallet consisting of two or several base members

ABSTRACT

Pallet consisting of several base members, which can have recesses for forks of a fork lift. The base members have holes perpendicular to the length of the members distributed along and closely adjacent the upper surfaces of the base members. Tubes inserted through the holes unite the base members to form the pallet. The base members consisting of three pressed carton pieces folded to a rectangular U-section, the length of each piece corresponding to the length of the base member. The first and the second pieces have a height substantially the height of the pallet. The third piece has an inner height dimension which is approximately the diameter of the tubes. The first carton piece in a base member has the U-section upright with the back of the U downwards, the second carton piece has the U-section as an inverted U-form disposed in the first carton piece. The third carton piece is located with its U-section upright and within and uppermost in the second carton piece. The distances between the vertical walls of the carton piece U-sections are dimensioned to fit closely to and in contact with each other, being tightly fixed by gluing. The holes for the tubes are located so the tubes lead through the space enclosed by the third carton piece uppermost in the base member. The said second carton piece can alternatively be the outer-most piece relative to the first and the third carton pieces.

BACKGROUND OF THE INVENTION

The present invention relates to pallets consisting of two or severalbase members provided with a number of holes adjacent or at a minordistance from, the upper load-bearing horizontal surface of the basemembers, through which holes tubes are inserted under friction to unitethe base members and form the pallet. The tubes do not require a specialstructure to fix them to the base members being kept in position due tofriction and the so-called drawer effect; the friction is considerablyincreased under load.

The base members of the type to which the invention pertains can,however, also be combined with each other by attaching a plate of asuitable material (board, plywood etc.) by, e.g., gluing the same to theupper horizontal surfaces of the base members, in which case theaforedescribed holes are not required or utilized. The plate then formsthe load-bearing plane. When tubes are used for combining the basemembers the load-bearing parts of the pallet are the upper parts of thetubes and the upper surfaces of the base members in combination. Ifdesired or required in view of the goods to be carried a pallet withtubes may be provided with one or more plates either located above thebase members or between the same, which form a smooth and continuousload-bearing plane.

SUMMARY OF THE INVENTION

A pallet of the type discussed above is described in WO No. 86/01786 . .. (PCT/SE85/00346) which is incorporated herewith as a reference. ThePCT patent application aims at achieving a pallet which can be handledby forks from all four sides, consisting of at least two base membersprovided with holes at the upper load-bearing surfaces and with recessesin the lower parts, intended to receive the forks of a conventionalfork-lift truck, which pallet has a very low weight, is cheap, has agreat flexibility as regards adaptability for different purposes, is notbulky when stored (since it can be stored in a non-completed state inthe form of its separate parts) and which, if desired, can easily bedestroyed after use by burning without formation of toxic or otherwisedisturbing gases. This pallet can be handled by a fork-lift truck fromall of the four sides; the forks can be inserted below the tubes fromtwo sides and into the recesses in the base members from the remainingtwo sides, which is desirable for rational handling and storage ofgoods.

The base members for the pallets according to the present invention,are, in comparison with many previously known base members, very cheapwhen manufactured in bulk and have a very low eight and a fullysufficient load-bearing capacity and fulfils commercial requirements.

The specific base member for a pallet according to the present inventionis characterized in that it is constituted by three pressed and foldedcarton pieces U-shaped cross section and with a length corresponding tothe desired length of the base member, of which the first and the secondpieces have a height corresponding to the height of the base member, andthe third pieces has an inner height approximately equal to the diameterof the tubes which project laterally through the base members. The firstcarton piece is located in the base member in the upright U-section withthe back or cross part of the U-section at the bottom, i.e., disposedagainst the floor. The second carton piece is located with the U-sectioninverted and inside the first carton piece; and the third carton pieceis located with the U-section upright and within and uppermost in thesecond carton piece. The distances between the vertical walls of theU-section, rectangular, folded carton pieces being such that they fitclosely to each other and by gluing are tightly fixed to each other atthe surfaces in contact with each other. The holes for the base memberjoining tubes are made through the space defined by the third cartonpiece uppermost in the base member so that the tubes are supportedbetween and by by the horizontal inner surface of the third carton pieceand the horizontal inner surface of the second carton piecealternatively, the second carton piece can be the outermost one.

The invention is further elucidated in connection with a preferredembodiment having recesses for forks and with reference to theaccompanying drawings, wherein:

FIG. 1 in perspective shows a pallet comprising base members accordingto the invention, consisting of three base members and seven tubes;

FIG. 2 in perspective shows the same pallet as FIG. 1 with one basemember in a partly cut-away condition;

FIG. 3 in perspective shows a section through a base member beside arecess for forks;

FIG. 4 in perspective shows a section through a base member at a recessfor forks;

FIG. 5 is an end view in perspective of a base member with an insertedsupport consisting of a cylindrical body;

FIG. 6 is an end view in perspective of a base member with anotherinserted supporting body;

FIG. 7 is an end view in perspective of a base member with an indicated,single angled gluing tongue for closing the lower end surface of thebase member;

FIG. 8 is an end view in perspective of a base member with two indicatedgluing tongues which after being glued overlap each other, for closingthe lower end surface of the base member;

FIG. 9 in perspective shows a plate for the formation of a flatcontinous loading surface on the pallet;

FIG. 10a-e show sections of alternative embodiments of the tubes whichcombine the base members of the finished pallet according to theinvention; and

FIG. 11 in perspective shows a complete pallet provided with tubesaccording to FIG. 10a.

The base members for the pallet according to the invention aremanufactured from one or several web materials, preferably a fiber-basedmaterial such as carton. The invention is elucidated below withreference to a preferred web material, viz. polyethylene-coated cartonwith a thickness of about 0.3-0.4 mms. but is in no way restrictedthereto; alternative web materials are obvious to the expert, e.g. solidboard or folding board. Such materials should have a suitable stabilityand strength and be submittable to pressing, folding and gluing. Thematerial should preferably have at least a certain degree of wetstrength.

Several layers of the above-mentioned polyethylene-coated carton areglued to each other to form a composite laminate material. One may use2-8 carton layers with intermediate glue layers, preferably 3-5 cartonlayers. This composite material has a great stability but can in spiteof that be pressed and folded. In certain cases it is preferred that thedifferent layers in the laminate are pressed separately and coated withglue as required, whereupon the composite material at an increasedtemperature, at which the glue or gluing substance does not adhere, isfolded to the intended form, whereupon the temperature is decreased forgluing the layers together. This procedure is especially advantageouswhen a great number of layers are used in the laminate. The number oflayers in the laminate should, of course, be adapted to the mechanicalstresses for which the finished base member is submitted.

Suitable glue products, which admit a rapid gluing, are commerciallyavailable. Thermoplastic glues may be used, e.g. in the emulsion form,optionally strengthened with a chelate-former, or glues of the hot-melttype.

As mentioned above, the base members for the pallets according to theinvention comprise three carton pieces 1-3 folded to what is called arectangular U-form, the length of which is equal to the intended lengthof the base member. A carton laminate is preferably used from which thepieces are pressed in a conventional manner. The design of the same isobvious in view of the drawings. The constructive features of the basemember is clearly shown in FIGS. 3 and 4.

More specifically, the base members comprise a first outwardly locatedcarton piece 1 (or carton laminate piece) which has been folded to therectangular U-form and rests with the U-shaped section upright and withthe cross piece of the U-shaped section against the floor. Inside thefirst piece 1, a second piece 2 is located which likewise has beenfolded to the rectangular U-form and is positioned with the U-shapedsection inverted and inside the first piece 1. A third carton piece 3disposed in the upright U-shaped manner is located within the secondpiece 2, uppermost therein, to form a space with an inner heightsubstantially equal to the diameter or vertical dimension of across-section of the tubes which unite the base members in the pallet.The three carton pieces shall carefully fit to each other and allcontact surfaces are glued to each other.

The holes 5 for the tubes 14 can be made in different manners. Thus, theholes can be pressed simultaneously with the pieces. Alternatively, theycan be pressed or cut with a circle saw or a cutting knife. Cutting witha high pressure water jet can also be used.

When desired that the base member be provided with recesses 13 forforks, the carton pieces 1 and 2 are designed accordingly as is obviousfrom the drawings and, specifically, so that the piece 1 is providedwith overlapping glue tongues 1a and 1b which after gluing to each otherform a bonding member 15 below the recesses 13. It is preferred tostrengthen the base member by gluing a stiff and strong band 4 (a stripof carton laminate) along the whole of its lower inner horizontalsurface, which band is embraced by the gluing tongues 1a and 1b.

In a corresponding manner the piece 2 is provided with overlappinggluing tongues 2a and 2b which, after being glued to each other, formthe upper horizontal surface in the recess 13 for the forks. In thismanner this part of the base member is strengthened which is ofimportance since the parts in question will take the full weight of theload when the finished pallet is handled by forks.

So as to give the base member an increased diagonal stiffness it ispreferred to insert in the ends of the base member suitable supports,e.g. in the form of a cylindrical body 10 made from a suitable material,such as a bobin piece with dimensions adapted to the space in question.Cross supports 11 may also be used, which can be made from the samecarton laminate as used for the base member. Such supports do not needto be attached to the base member, they can quite simply be insertedunder friction.

An alternative is to give the base member the required diagonalstiffness by using gluing tongues which continue from pieces 1 and/or 2.Such gluing tongues can be simple ones 8 or double 9a and 9b. A simplegluing tongue is glued inside the base member, whreas the double tonguesare glued to each other.

In view of the explanations above and the drawings, especially FIGS. 3and 4, it is obvious that the pieces 1 and 2 can switch places withoutany loss of strength.

For manufacturing-technical reasons as well as economical it ispreferred to prepare the connecting tubes from the laminate describedabove for the base members. In FIG. 10 different alternatives for thecross section of such tubes are shown. The tubes are folded as shown inthe drawings with gluing surfaces to the formation of tubes with anessentially rectangular form. FIG. 10c, however, shows an openU-section, which may be sufficient for pallets intended for easy loads.FIG. 10e shows a tube with a triangular cross-section. FIG. 10d shows insection a tube, the bending strength of which has been increased by adiagonally located integral laminate portion. For these tubes a laminatecomprising 8-12 carton layers are preferably used, glued to each otherwith a glue of the type mentioned above. In the pallet the tubes may belocated in the position shown in FIG. 10, but they may also be inpositions turned e.g. 90° from the one shown.

It is, of course, also possible to use conventional round tubes of anykind of material for connecting the base members with each other.

So as to provide the pallet comprising base members and tubes accordingto the invention with a plane loading surface it may in some cases besuitable to cover the loading surface with a plane 7 provided withguides 16, the width of which corresponds with the distance between thebase members. Alternatively, planes solely between the base members canbe used.

A preferred carton material for the laminate for the base membersaccording to the invention is the hydrofobic polyethylene-laminatedcarton with the thickness defined above. Pallets are often used out ofdoors under moist conditions. The preferred polyethylene-coated cartonmaterial is not per se water-absorbing due to the outermost locatedpolyethylene layer. A certain slow absorption of water occurs at theedges of the material. This can however, be prevented by application ofa moisture barrier on these edges. As the moisture barrier numerousdifferent materials known per se can be used, such as fats, waxes,suitably in the molten state so as to avoid the use of toxic solvents.It is preferred to use the glues defined above for the laminate for thispurpose.

The lower surfaces of the base members which are in contact with theground can, so as to strengthen the existing thin water-repellingpoly-ethylene layer, be provided with a wear-resistant surface coating,if so required. Such a coating can be made with the use of manydifferent materials, such as an extra layer of the laminate used for thebase members, a thicker layer of polyethylene fixed thereto by meltingor similar.

The invention has been described with reference to a specificembodiment. It is obvious that modifications of the base member can bemade without deviation from the inventive concept. Such modificationsare obvious to the expert on the basis of the guidance and descriptiongiven above and in the accompanying drawings and such modifications areintended to fall under the scope of the claims.

We claim:
 1. Pallet consisting of at least two elongate base members having upper and lower, surfaces and side surfaces said base members having a number of holes provided laterally through the side surfaces perpendicularly to their elongate length directions, distributed along and closely adjacent the upper surfaces of the base members, through which holes, tubes can be inserted under friction so as to unite the base members to the formation of the pallet, characterized in that: each base member of the said pallet consists of three pressed carton pieces (1,2,3) folded to a rectangular U-section, each piece having a length corresponding to the length of the base member, of which the first (1) and the second (2) U-section carton pieces have a height corresponding substantially to the height of the pallet, whereas the third U-section carton piece (3) has a height dimension of the inner surface of its upright portions of its folded U-section which approximates the diameter of the tubes; of which folded carton pieces, one of the first (1) and the second (2) U-section carton pieces in the assembled base member is disposed in the upright U-form with the back of the U-section downwards, the other of the two U-section carton pieces (1,2) is disposed in the inverted U-form and situated within the said one carton piece (1 or 2) and wherein the said third U-section carton piece (3) is located in the assembled base member in an upright U-form disposed within and uppermost in said other U-section carton pice (1 or 2), the distance between the vertical walls of the carton pieces folded to the rectangular U-form being such that they fit closely to each other and by gluing are tightly fixed to each other at surfaces in contact with each other, the holes for the tubes being located so as to lead through the space enclosed by the third carton piece (3) uppermost in the base member, whereupon the tubes are supported by the horizontal inner surface of the third U-section carton piece (3) and by the horizontal inner surface of the other of said U-section carton pieces (1 or 2).
 2. Pallet according to claim 1, characterized in that, in the base members thereof, the first (1) and the second (2) U-section carton pieces, each are provided with pairs of gluing tongue pieces (a) and (b) at the location of each of said recesses (13), which tongues, after folding and gluing to each other, form the upper horizontal surface and the lower horizontal surface in the recesses
 13. 3. Pallet according to claim 2, characterized in that its base members' inner lower horizontal surfaces are strengthened with added stiff and strong carton material laminate strips (4), the width of which optionally corresponds to the inner width of the base members and which run along the whole length of the base members and below the gluing tongues (1a, b or 2a, b) present at the lower end of the recesses for forks.
 4. Pallet according to claim 2, characterized in that the three U-section carton pieces (1-3) in the base members thereof are pressed from a web material selected from polyethylene-coated carton, folding carton or solid carton.
 5. Pallet according to claim 4, characterized in that the web material for the base members has a thickness in the range 0.2-1.0 mms., especially 0.3-0.5 mms.
 6. Pallet according to claim 4, characterized in that the three U-section carton pieces (1-3) and the strips (4) in the base members are pressed from a laminate of such web materials, said laminate comprising from 2-8 layers of the web material glued to each other.
 7. Pallet according to claim 1, characterized in that a glue is used in the base members so that the three carton pieces (1-3) in the base members have been fixed to each other and the strips (4) have been attached with said glue and said glue is a thermoplastic emulsion glue.
 8. Pallet according to claim 1, characterized in that the outer ends of the base members therein have been closed with at least one glue tongue (8).
 9. Pallet according to claim 1, characterized in that the outer ends of the base members therein have been diagonal-strengthened with inserted bodies (10), suitably of the same material as the base member.
 10. Pallet according to claim 6, characterized in that the said tubes are made from said web material, which when used for the tubes comprises 8-12 laminate layers, which after cutting are folded and glued to an essentially rectangular form.
 11. Pallet according to claim 1, wherein said first U-section carton piece (1) is said one U-section carton piece and said second U-section carbon piece (2) is said other carton piece and said third U-section carton piece (3) is located within and uppermost in the second U-section carton piece (2).
 12. Pallet according to claim 1, wherein said second U-section carton piece (2) is said one U-section carton piece and said first U-section carton piece (1) is said other carton piece and said third U-section carton piece (3) is located within and uppermost in the first U-section carton piece (1).
 13. Pallet as defined in claim 1, wherein said side surfaces of each base member are shaped to provide through passage recesses, having upper and lower surfaces, in the lower portions of said base members for enabling passage of the forks of a fork lift truck through the base members of a pallet.
 14. Pallet according to claim 7 wherein said emulsion glue includes the addition of a chelate-former.
 15. Pallet as defined in claim 9, wherein said inserted bodies (10) are formed as standing cylinders with vertical axes, made from the same material as the U-section carton pieces.
 16. Pallet as defined in claim 9, wherein said inserted bodies are formed as diagonal cross members made from pieces of the same material as the U-section carton pieces.
 17. Pallet as defined in claim 10 wherein said tubes are folded and glued to an essentially triangular form. 